Enhanced alkene productivity in methanol-to-hydrocarbons conversion using a secondary catalyst component and hydrogen co-feeds
Abstract
The methanol-to-hydrocarbons conversion over unidimensional 10-membered ring zeolites offers an attractive route to produce C 3 –C 5 alkenes, central building blocks for the production of sustainable aviation fuels. However, the application of such zeolites is limited by a rapid deactivation due to coke formation. We present a novel catalyst design concept to significantly enhance coke resistance, achieved by physically mixing the zeolite with a secondary catalyst component exhibiting hydrogenation activity and operating under near ambient-pressure hydrogen co-feeds. Among the tested materials, Pd/SiO 2 provides the highest stability enhancement, leading up to 10× higher cumulative productivity of C 3 –C 5 alkenes, and outperforming a bifunctional Pd-loaded zeolite. The enhancement is observed across a broad range of hydrogen concentrations and zeolite:Pd/SiO 2 weight ratios, offering flexibility to minimize hydrogen and Pd use. Kinetic and spectroscopic investigations reveal that Pd intercepts coke-forming intermediates, such as formaldehyde and dienes, thereby reducing the rate of internal and external coke deposition.